Not Sure What I'm Doing Wrong

If you've been following my log, you'll see that I'm trying to gain some size, because right now I don't feel like I'm someone you'd look at and say "yeah, he lifts." If you haven't, for reference I'm 19, 5'7" and as of this morning 150lbs. The last time I took measurements was June 6th, as follows:

Since then, I've done some "checkpoint" measurements and I've gained no size except for my forearm which are at 12" now. Thanks to my job I've been at for a month now (commercial lawn care and landscaping, Monday - Friday 6:30am to 5pm).

I've been going to the gym about 4 days a week on average, depending on how hard of a day at work it was. My calorie intake on work days is at least 3200, some days it goes over 4k.

I'll wake up some mornings at 156 and 3 days later I'm back down to 150 or 149.8.

I was doing 5/3/1 and wasn't seeing or feeling anything, I was never sore and sometimes I couldn't hit the weight I "needed". I've switched it up a little bit doing more volume (5 sets of 10) and that's the only way I ever get sore or anything.

Anyway, back on topic. I'm not quite sure what I'm doing wrong, I haven't gained any size at all but, I will say this, I've gained LOTS of strength in ALL of my lifts, especially anything with upper back involvement (thank you job, again).

If you have time to check out my log, and look at my lifts of when I started it and my most recent, you'll see my strength has improved a lot.

If you are gaining strength you will likely gain size down the road. Make sure you are logging you actual calories and not just guessing. It hasn't been that long since you last checked measurements. Give it some time, muscle isn't built over night.

If you are gaining strength you will likely gain size down the road. Make sure you are logging you actual calories and not just guessing. It hasn't been that long since you last checked measurements. Give it some time, muscle isn't built over night.

Oh yeah, I track actual calories, but as a "weekly average" my app says 3156 calories a day, but it varies daily.

Strength gains have definitely been noticeable, for sure, I hope the size comes sooner than later.

Though, my size medium shirts don't fit in the chest and back anymore. And my major strength increases have been there, so I may have gained some size there. But my upper arms are severely lacking in both the strength gains and size gains.

A couple key points for gaining overall size is, as others have mentioned eating a surplus of cals.
You also mention your job as a lawn care worker, which is a very physically active job that will deplete calories faster than a sedentary or less energetic job. Combine that with lifting and you might need to eat more if you are looking to gain bw.
Personally, I might just believe you are not being patient for one, and just need more time under the weights. Just because you are showing your BW on a scale does not mean you are spinning wheels. With your active job, you may very well be replacing some of your bodyfat with lean tissue, which will not show up as an overall weight gain on the scale, but will show up as strength gains and some new muscle.
Your also quite young with most likely nervous energy which takes up cals. I would be patient and stay your course, maybe "slowly" add in some more food over time. You will gain, believe me. IMO, try and make more of your concentration, adding weight to the big compound exercises, your body will compensate by adding size and beefing your appetite to keep up and do not worry so much about measuring and size all the time. It will come.

I started lifting when I was 16. I am sure I was eating north of 3500 calories per day easy (at 6'3 and 170#). I could never break over 170# no matter what I ate...and I never stopped eating (anything and everything all day long). I never really saw any muscle definition either, but I kept at it because I have always loved the freeweights. When I was 18 I took a weightlifting course in college and still no change at 170#.

Soon after turning 20 my muscles just exploded, and I never changed anything much with my routine or intensity. Just kept alternating between upper and lower body days with a basic freeweight program. When I was 21 I hit 220# and I remember my sister saying I looked like some kind of monster.

Now that I am 44 I have traded the monster look for the lean/athletic look. I am 205#, 10% bf, and take in 2200 calories a day of natural food and avoid anything processed except for an occasional cheat. If I take in 2800 cals then my weight marches up. Switch back to 2200 cals and it goes back to 205 but *never* falls below that, even if I cut the cals down to 2000 there is no effect in weight loss, so I just cruise at 2200. My workout program is 5/3/1.

Anyways, don't get frustrated. You have no idea what your body is going to do until you finish growing. People will hit you with the cals in/cals out story like it came from the bible, but everybody is different and everyone's system will respond differently to a calorie deficit or surplus.

Just do this: always keep lifiting. It's great for your muscles, bones, mind, and spirit. Your persistence will pay off huge dividends when middle age comes and all your friends look um, middle-aged, while you look and feel like a million bucks. Trust.